1. Field of the Disclosure
This disclosure generally relates to a touch device, more particularly, to a touch device and a signal processing circuit as well as an operating method thereof that may reduce the offset error caused by the offset voltage of an operational amplifier to increase the signal dynamic range.
2. Description of the Related Art
Touch device or touch panel is used to detect touch signal resulting from a touch event or press event. The detection signals outputted by the touch panel are successively processed by an analog front end and a digital back end to accordingly identify whether the touch panel is operated by a user.
The analog front end may adopt an integrated programmable gain amplifier (IPGA) as shown in FIG. 1 to amplify the detection signals. The IPGA includes an operational amplifier which has an offset between two input terminals due to the manufacturing process, and this offset causes an offset voltage which can reduce a signal dynamic range of the digital back end connected downstream such that the signal-to-noise ratio (SNR) and the operating performance of the touch panel are degraded.
Accordingly, the present disclosure provides a touch device and a signal processing circuit as well as an operating method thereof that may eliminate or at least significantly alleviate the signal dynamic range decrease caused by the offset voltage of the operational amplifier.